Telephone-transmitter.



v A. P. PINKLER. TELEPHONE TRANSMlTTER.

APPLICATION FILED MAY 1.0. 1916.

1,297,905. Patented Mar. 18,1919.

T UFFTE ARTHUR P. PINKLER, OF RIDGEFIELT), NEW ERSEY, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-TRANSMITTER.

To all whom it may concern:

Be it known that 'I, ARTHUR P. PIN'KLER, a citizen of. the United States, residing at Ridgefield, in the county of Bergen and State of New Jersey, have invented certain new and useful Improvements in Telephone- Transmitters, of which the followiilg is a full, clear, concise, and exact description.

This invention relates to telephone transmitters and more particularly it relates to that type of transmitter or microphone used as an aid to those hard of hearing and in detective work, and in general where the transmitter is located at some distance from the source of sound to be transmitted. The object of this invention is to provide a microphonic transmitter of extreme sensitiveness and uniform operation.

This invention, therefore, provides an improved design for such a transmitter, the main feature of which is a vibrating soundreceiving diaphragm having molded, or otherwise formed therein, a plurality of cupshaped pockets which function as containing chambers for the comminuted resistancevarying material. An electrode supported opposite the openings of said pockets serves to retain the comminuted'material in the pockets, and acts as a stationary electrode for all of the pockets in common. This and other features of novelty will be more clearly understood by reference to accompanying drawings, in which Figure 1 represents a sectional perspective view of the transmitter of this invention; Fig. 2 shows in cross-section an alternative method for clamping the vibrating diaphragm in place; and Fig. 3 shows a front view of the assembled transmitter.

Referring to the drawings, .4 is a casing, preferably of metal having an upturned edge 5, which acts as a support for the periphery of the diaphragm G. In theconstruction shown in Fig. 1, diaphragm 6 is held against the rim by means of a tripodal spring here shown in section, having an annular. central portion 8, which bears against the cover 10, and three extensions 9, which are bent down from the annular portion 8 and,bear on the periphery of the diaphragm 6. The cover 10 is held in place'by means of screws 11, suitably disposed around the periphery of the case. In the arrangement shown in Fig. 2, the diaphragm is Specification of Letters Patent.

Patented Mar. 18, 19119.

Applicationfiled May 10, 1918. Serial No. 96,497.

clamped tightly against the rim 5 by means of cover 12. In each case, the cover 10 or 12 has a central opening 13 for the admission of sound waves. Diaphragm 6 is pref erably of pressed carbon, and has at its center a number of cup-shaped receptacles 14, which are preferably molded in the diaphragm. Seven of these cups, for example, may be conveniently arranged in the manner shown but it is to be understood that any number of such cups, in any convenient arrangement, may be employed. The formation of the cups H in the diaphragm makes possible the maximum agitation of the comminuted material 15 without unduly increasing the mass of the vibrating diaphragm.

Opposite the openings of the caps 14 is an electrode 16, having a small rod or stem 17 soldered to its back at 24. Rod 17 projects through an eyelet 18 which is riveted through an opening 19 in the back of the case 4, and insulated therefrom by insulating washers 20. In the adjustment of such an instrument, it has been found convenient and decidedly effective to place between the electrode 16 and the diaphragm 6 a separator having a thickness equal to the separation ultimately desired at 21, between the electrode and the diaphragm. The transmitter is then turned on its face and the electrode 16 allowed to fall downward into position and fastened permanently in place by a drop of solder at 22. If desired, a terminal clip 23 .may be riveted under the eyelet l8 as shown. The comminuted material is preferably in the form of. small carbon pellets, and the space 21 is adj ustcd to be sufficiently less than the diameter of such pellets to insure that they will be properly retained in the chambers 1i and will not become wedged between the edge of the cups and the stationary electrode v16.

\Vhat is claimed is 1. A telephone transmitter comprising a Vibratory diaphragm adapted to be actuated by sound waves impinging upon one side thereof, a plurality of pockets therein, the total wall surface of said pockets located on the side of said diaphragm on which sound waves are designed to impinge being,

greater than the geometrical projections of said pockets on the plane of said diaphragm, connninuted material. in Sal-Kl pockets, and 

